the comparative analysis of manual and rotary techniques for gutta percha

8/19/2019 The Comparative Analysis of Manual and Rotary Techniques for Gutta Percha

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Romanian Journal of Oral Rehabilitation

Vol. 4, No. 4, October - December 2012

17

THE COMPARATIVE ANALYSIS OF MANUAL AND ROTARY

TECHNIQUES FOR GUTTA-PERCHA AND SEALER REMOVAL1*

, Andrei Iliescu2, Loredana Precup

3

1Department of Odontology, Periodontology and Oral Medicine, University of Medicine and

Pharmacy, T rgu-2Department of Endodontics, University of Medicine and Pharmacy, "Carol Davila"

3

*Corresponding author: , Department of Odontology, Periodontology and Oral Medicine

University of Medicine and Pharmacy, -

38 Gh. Marinescu Street, E-mail: [email protected]

ABSTRACT

The purpose of this study was to assess in vitro the efficiency of nickel-titanium rotary files and hand files for

removal of endodontic filling using orange oil as a solvent. Forty extracted molars and premolars were selected.

They were divided into 4 groups with curved or straight canals. Half of these were filled using the warm lateral

condensation technique and the other half using the single-matched taper-sized cone technique. They were

retreated using hand files and rotary files for each filling technique. Each root canal was sectioned in the coronal

third, mid third and apical third. All the sections were analysed using an endodontic microscope at the highest

magnification. The findings of this study showed that none of the retreated canals were completely free of gutta-

percha and sealer remnants. The mixed use of manual and rotary files can lead to a more efficient cleaning

though curved canals remain a challenge.

Keywords: endodontic retreatment, manual files, rotary instruments, ProTaper system

INTRODUCTION

The failure in the endodontic treatment is

still present despite the evolution of the

instrumentation techniques and of the

instruments used in endodontics, due to

extremely complicated anatomy of the

endodontic space, to the microflora that

resides in this space in various pathological

In 1989 Wilcox [1] underlines the fact that

the success of endodontic treatment is directly

influenced by the removal of gutta-percha and

sealant in their entirety. On apical level, this

goal is essential and the manual removal

methods are the ones advised for optimal

efficiency.

The removal of the endodontic filling can

be done using several techniques: manual files

with or without the use of solvents, classic

rotary instruments (Gates-Glidden) and

special rotary nickel-titanium, brought on the

market by several companies that

manufacture nickel-titanium instruments for

chemo-mechanical treatment. Also, modern

techniques make use of ultrasounds and laser.

Objective

In this study two methods of endodontic

filling removal were compared: manual and

rotary on previously sealed canals, using cold

lateral condensation or single calibrated cone

technique.

MATERIAL AND METHODS

40 molars and premolars with curved canals


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between

cavity was opened with the high-speed and

low-speed hand piece resulting in the

identification of 98 canals of which 64 straight

and 34 curved. The working length was

determined with the K-10 file with a 0.5 mm

withdrawal from the moment of visualizing the

tip at apical level. They were prepared using

ProTaper, Densply until the F2 file at 300 rpm

Irrigations with sodium hypochlorite 5.25%

were performed, and EDTA and alcohol at the

end of the chemo-mechanical treatment.

During the process, four files fractured on the

randomly placed in two lots of 20 teeth and 49

canals, they were filled using the cold lateral

condensation technique or calibrated single

cone technique with standardised cones from

ProTaper system, Densply and as sealant

Apexit from Ivoclar Vivadent. After 3 days

they were divided in 4 lots: A, B, C and D of

10 teeth, summing up to 24 / 25 canals of each

lot. Retreatment was performed using manualfiles, or rotary files for retreatment from

ProTaper System, Densply. Orange oil was

used as a solvent. Lot A was filled by the

single cone technique and retreated manually,

group B was filled by lateral condensation and

retreated manually, group C was filled using

the single cone technique and retreated with

the rotary procedure and group D was filled by

lateral condensation and retreated with the

rotary procedure as well. For the rotaryretreatment there were used special retreatment

files from the ProTaper Universal D1 series

(removes the obturation at coronary level), D2

(removes the obturation at medium level), D3

(removes the obturation at apical level) at 500

After the complete filling removal each tooth

was sectioned at cervical, medium third and

apical level. They were examined at the

operative endodontic microscope at a 24.9Xmagnification for the evaluation of residual

obturation remains. Scores were given to

evaluate as precisely as possible the degree of

retention of the obturation on the radicular

walls. The nature of the identified material was

also mentioned: sealant, gutta-percha or DDR

(remaining dentinar detritus) due to inefficient

irrigation. This was considered:

0 - without traces of obturation

1 - traces of sealant

diameter

1G - traces of sealant and gutta-

2 -


3 - traces of obturation (counted islands)


4 -

the cana


.

RESULTS

In case of group A it was noticed that in

the coronary third there was obturation

material including gutta-percha, fitting the 1G

category in 45.83 of the cases, 2G in 12.05%

of the cases and 3G in 8.33% of the cases

found in the curved canals (for the 3G score).

At the level of the medium third the highest

percentage 29.16% is also for 1G, 12.50% fits2G and for the rest the obturation is optimal.

At apical level in 12.5% of the cases the score

was 1G and 8.33% has proven to be 4G; these

scores appeared only due to the curved canals.

In a large proportion the presence of DDR

was noticed at the level of the apical third,

66.66% of the cases, of which 25% were

present at the level of curved canals.

The manual retreatment technique of lot B

leads to optimal results in the coronary thirdwith obturation material remaining only in


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12.5% of the cases fitting score 1. In the

medium third the remaining gutta-percha fits

3G (20.83%) and 1 (12.5%) mainly because

of the finding of obturation material and

gutta-percha in curved canals (3G 20.83%,

1 8.33%). At apical level the gutta-percha

residual value increases in the 4G score

(20.83%), fact explainable also by the

presence of 3 cases of instrument fragments at

that level of curved canals. Also, in 16.66% of

the cases there is remaining dentinar detritus

of which 8.33% was found in channels with

curves.

Fig. 1. Traces of endodontic gutta-percha and

sealer

In the lot C the following were noticed: the

residual obturation material at the coronary

endodontic level fits the score 1 in 28% of the

cases, the rest of the cases showing optimal

removal. At medium level 56% of the cases

filling was optimally removed, 12% were in

score 1 and 4% were in score 4G, in the last

case the recordings being made at the level of

the curved canals. At apical level the filling

removal has proven to be efficient, only 8%

of the cases fitting the 4G score result due to

the analysis of curved canals. The dentinar

detritus reached 80% although.

The rotary filling removal technique in lot

D had optimal results at the level of the

coronary third in 80% of the cases and sealant

remains score 1 in 12% of the cases and score

2 in 8% of the cases. In the case of the

medium third the removal of the obturation

has proven to be efficient in 68% of the cases

with gutta-percha remnants with scores of 1

and 2 in only 16% of the cases and 3G and 4G

also in 16% of the cases. At the apical level

40% showed traces of DDR, 13% showed the

4G score and 75% were optimally retreated.

The optimal retreatment at coronary level

is recorded in teeth group B (87.5%), at

medium level in group D (68%) and at apicallevel in group C (88%). Scores of apical 4G

were recorded in the case of lot B (20.83%)

and D (13%). In group B the percentage of

20.83% is found for the 3G score in the

medium third.

Fig. 2. Graph showing the percentage of 0 score for each radicular level in the four groups.


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DISCUSSIONS

The removal of the whole content of the

endodontic system is necessary to assure the

optimal chances for disinfection and healing

of the pathology following the microbacterial

charge at the endodontic level. The curved

canals make the retreatment a lot more

difficult at the medium and apical levels.

Recent studies prove that no matter of the

used technique remains of sealant and/or

gutta-percha remain at the endodontic level

[3]. In addition, the apical area is the one with

the richest ramification and with the greatest

variation in morphology which makes even

more difficult the removal of this area both

for the obturation material and the resulting

debris.

A series of retreatment techniques were

tested to find the most efficient, the easiest

and fastest method of gutta-percha and canal

sealant removal, but many studies show the

fact that the manual instrumentation plays a

significant role [4, 5].

The nickel-titanium instruments arerecommended by the manufacturers for the

speed and ease with which they fulfil their

purpose and because of the physical

properties they possess, the literature also

mentions their capacity to soften the gutta-

percha due to the heat developed by friction.

The later use of manual files will successfully

remove the gutta-percha dislocated by the

rotary files. It is said that the pairing of the

rotary filling removal with the manual one isindicated in order to reach an optimally

cleaned endodontic space [5, 6].

Chloroform is one of the most used

solvent from the existing ones. In spite of the

fact that there have been studies that

incriminated it for being extremely toxic, its

maximum toxicity is highlighted when it

reaches the periapical tissues, an accident that

should be avoided for the majority of solvents

and irrigants with disinfecting properties. Its

toxicity when the accident above is avoided

or as a consequence of inhalation the

minimum quantity needed to dissolve the

gutta-percha are neglectable. In this study we

have used the orange oil as a solvent because

its ability of softening the gutta-percha is

lower, thus enabling the analysis of the

aspects related to the instrument used in

retreatment [7].

In this study, the files used for the chemo-

mechanical treatment were from the same

manufacturer, in order not to modify the

conicity and to maintain the shape after the

filling removal of the canal obtained in the

initial treatment.

The risk of perforations, ledges and false

ways depend on the type of instrument and

movement used and also on the existing

difficulties following the primary treatment.

Studies on retreatment assess the degree of

filling removal by a radiographic analysis of

the filled canal. We have aimed for a 3D

analysis accessible in practice, and we used it

after sectioning the teeth to evaluate

maximum efficiency with the endodonticmicroscope Zeiss Opmi Pico.

The calibrated cone filled teeth left less

material on the apical level than on the

coronary level because in the moment of the

dislocation the cone removed in one peace.

The rotary retreated cases left less remaining

material in the medium third and apical

because of the direct action of the file on a

certain portion of the canal as a consequence

of the special design with progressiveconicity of the retreatment files.

CONCLUSIONS

1. The retreatment with rotary or manual files

never yields a perfectly clean canal,

without obturation material remains.

2.

The mixed use of manual and rotary files

can lead to a more efficient filling removal

from the endodontic space due to the

increase in speed when using the rotary

files.


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3.

Using solvents helps the softening of the

gutta-percha and eases the advancement

and efficiency of the rotary and manual

files.

4.

The magnification provided by the

endodontic microscope is essential in

tracking the remaining residue and in

facilitating its removal.

5. The cold lateral condensation obturation is

harder to remove as it is more compact and

6.

The curved canals remain a challenge; the

success in their retreatment depends a lot

on the use of magnification, of solvents, of

quality files and of their manipulation

without force at the rotation recommended

by the manufacturer.

REFERENCES

1. Wilcox LR. Endodontic retreatment: ultrasonics and chloroform as the final step inreinstrumentation. J Endod 1989; 15:125-128.

2. Khatavkar R, Hedge V: Current concepts in gutta-percha removal for retreatment. Dental Tribune

2010, April-June, 18.3. Reddy S, Neelakantan P et al. Removal of Gutta-percha/Zinc-Oxide-Eugenol Sealer or Gutta-

percha/Epoxi Resin Sealer from Severely Curved Canals: An In Vitro Study. International Journal ofDentistry 2011; 8:1-6.

4. Ferreira JJ, Rhode JS, Pitt Ford TR. The efficacy of gutta-percha removal using ProFiles Int Endod J2001; 34:267-274.

5. Betti LV, Bramante CM. Quantec SC rotary instruments versus hand files for gutta-percha removalin root canal retreatment. Int Endod J 2001; 34:514-519.

6. Sae-Lim V, Rajamanickam I, Lim BK, Lee HL. Effectiveness of ProFile.04 taper rotary instrumentsin endodontic retreatment. Int Endod J 2000; 26:100-104.

7. Bueno, C. E., Delboni M.,G. Effectiveness of Rotary and Hand Files in Gutta-percha and SealerRemoval Using Chloroform or Chlorhexidine Gel. Braz Dent J 2006; 17(2): 139-143.

the comparative analysis of manual and rotary techniques for gutta percha

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